Use of Iron-Containing Mesoporous Carbon (IMC) for Arsenic Removal from Drinking Water

Abstract

While great progress has been made in nanotechnology in recent years, application of engineered nanomaterials to environmental protection has been less explored. In this study, iron-containing mesoporous carbon (IMC) was prepared from a silica template (MCM-48) for effective removal of arsenic from drinking water. The synthesis began with in situ polymerization of resorcinol with formaldehyde (RF) in the porous structure of the silica template in a basic aqueous solution, followed by carbonization in an inert atmosphere and template removal. The IMC was obtained by impregnating ferrous chloride into mesoporous carbon followed by sodium hypochloride oxidation. Prepared IMC had a BET specific surface area of 401 m²/g, slightly lower than the surface area of 503 m²/g for the mesoporous carbon. Transmission Electron Microscopy micrographs showed the existence of mesoporous structure in IMC. The adsorption of arsenic (As^III and As^V) from drinking water by IMC followed the Langmuir adsorption model, with the adsorption maximum reaching 5.96 mg As/g for arsenite and 5.15 mg As/g for arsenate. Based on the amount of impregnated iron and the maximum arsenic adsorption, the calculated molar ratio of iron and arsenic was 7.81–8.40. A pseudosecond-order adsorption kinetic model can fit the adsorption data well.